By the looks of the most recent report from the Office of Congressional Ethics, the first six months of 2015 were some of the busiest since the agency launched six years ago, at the beginning of the 111th Congress. But lawmakers remain lax about policing themselves.

On July 31, the House Ethics Committee announced it was closing a review of nine lawmakers who took an all-expenses-paid trip to Azerbaijan that might have been secretly funded by the country's state-owned oil company. The panel cleared lawmakers of wrongdoing and, in an unprecedented step, stopped short of releasing the findings of the OCE's probes. After an "extensive investigation" involving 12 subpoenas, 10 witness interviews and nearly 190,000 pages of documents, the committee stated it could not complete its investigation because many potential witnesses from foreign countries refused to cooperate. The 28-page reports states Kemal Oksuz, the chairman of the two nonprofits alleged to have secretly coordinated with the State Oil Company of the Azerbaijan Republic to sponsor travel, refused to cooperate.

Though the committee uncovered "evidence of concerted, possibly criminal, efforts by various non-House individuals and entities to mislead the House travelers and the Committee about the Trips' true sponsors and the funding sources used to pay for Member and House employee travel to Azerbaijan," that evidence was not conclusive. It will be referred to the Justice Department for further review.

A July 2014 report from the Houston Chronicle initially sparked the interest of ethics watchdogs. The committee staff did not find anything that was necessarily problematic, but apparently kept digging.

On Jan. 29, the Office of Congressional Ethics notified the Ethics Committee it had initiated 10 preliminary 30-day reviews into Azerbaijan travel allegations. From January to June of this year, the OCE launched 19 such reviews. That's more cases than were launched in all of 2012, 2013 and 2014.

On March 2, the OCE notified the committee it was moving into its second phase of review for nine lawmakers — six Democrats, including one member of the ethics panel, and three Republicans.

On March 4, House Ethics Chairman Charlie Dent , R-Pa., and ranking member Linda T. Sánchez, D-Calif., sent a letter to the OCE formally requesting the quasi-independent agency cease its review of the trips and refer the matter immediately to the committee.

According to the report, the committee asked the OCE to halt because it had an ongoing investigation, and because it had already requested information from relevant parties. "Second, the Committee possessed more complete information than OCE and is uniquely qualified to handle the matter," the report states.

Despite the request, the OCE continued its review. On May 8, it referred its allegations to the committee.

Five days later, The Washington Post reported 10 lawmakers and 32 congressional staff members received hundreds of thousands of dollars' worth of travel expenses and more than $2,500 worth of gifts as part of the May 2013 trip. The report cited a 70-page OCE document, obtained by the Post, and stated congressional investigators found no evidence members or staffers knew that the conference, titled "U.S.-Azerbaijan Convention: Vision for the Future," was being funded by a foreign government.

On July 31, the Ethics Committee declared the case closed without making that 70-page report public. It instead published one-page summaries of all nine reports. The committee noted the OCE's ultimate "findings" were considered "supporting documents" because they arrived after the cease-and-refer request.

The committee also blamed the unauthorized leak to The Washington Post for making its job harder. Although the review is inconclusive, ethics investigators "did not uncover any evidence of wrongdoing by and House member, officer or employee," according to the report.

Travel disclosure forms must be filed to the committee 30 days before the trips and require travel sponsors to disclose if the entity footing the bill is a federal lobbyist or foreign agent. Lawmakers must disclose if the sponsor employs either federal lobbyists or foreign agents.

Although the Ethics Committee failed to enforce the 30-day timeline at the time of the Azerbaijan trips, as USA Today first reported, the committee blames the nonprofits for concealing any alleged ties to SOCAR.

"Each of the non-profits, in required disclosure forms filed with the Committee, certified that it was the sole sponsor of its trips," the committee noted. "Each non-profit also stated that it had not accepted funding from any other source to directly or indirectly finance any portion of the Trips."

Thus, the lawmakers do not have to repay any travel expenses. In one case, the bill topped $24,000.

While in Azerbaijan, several travelers accepted gifts. But many told the committee the gifts were left in their hotel rooms, with no indication of who provided them.

On July 16, the committee sent letters to six members who received "tangible gifts" during the trips and still had them in their possession, recommending they return or "otherwise remedy" the gifts. All six members complied immediately, the report states.

During the final week before the August recess, House lawmakers involved in the Azerbaijan trip were largely quiet about the probe.

Rep. Leonard Lance, R-N.J., took a nearly $9,800 trip funded by the Council of Turkic American Associations, according to his disclosure form. The group has sponsored 28 trips totaling more than $110,000 — largely for Democrats — since 2011, according to a database maintained by Legistorm. In May 2013, the CTAA also flew New York Democrats Gregory W. Meeks and Yvette D. Clark to Azerbaijan. Clark is a member of the Ethics Committee.

"The trip I took was to Turkey and, as an adjunct to that, I was in Azerbaijan a day and a half. But the whole trip, including travel across the ocean, was nine days. So the overwhelming preponderance of the trip I took was to Turkey," Lance told CQ Roll Call during a July 28 interview in the Speaker's Lobby. He said, when asked, that the probe would not deter him from accepting future privately sponsored trips that were "fully vetted" by the committee. Lance did not identify the CTAA by name.

"Lots of members have gone to Turkey and yes, the New York-New Jersey group has been responsible for prior trips to Turkey. I would not have traveled to Azerbaijan as the principle focus of the trip," Lance emphasized. "The principle focus of the trip I took was to Turkey. I flew to Turkey, and I flew home from Turkey; and in the interim, for a day and a half, I was in Azerbaijan."

Clark and Meeks did not respond to inquiries for this story. Clark's trip cost $8,700; for Meeks the bill was around $6,400.

The Turquoise Council of Americans and Eurasians, a group that's funded more than $202,000 in congressional travel since 2010, financed Azerbaijan travel for Texas Democrats Rubén Hinojosa and Sheila Jackson Lee, New Mexico Democrat Michelle Lujan Grisham, and Republican Reps. Jim Bridenstine of Oklahoma and Ted Poe of Texas. None of the lawmakers, whose trips ranged in cost from $12,000 to $19,900, responded to Speaker's Lobby interview requests.

Rep. Danny K. Davis, D-Ill., who is under review for Azerbaijan travel sponsored by the Turkish American Federation of Midwest said the experience "caused me to do a different level of scrutiny, in terms of vetting."

"Normally when I get an invitation, whoever gives it to me, 'Hey, OK, is this something we can do? Is this something we have time to do? Is this something we want to do?' and whoever is represented as being the sponsor, we pretty much take that at face value. Now it means I'll do a little more checking," he said.

The group, a non-governmental organization with more than 40 institutions under its umbrella, has funded more than $260,000 in congressional travel since 2011 and continued to sponsor trips for Congress as recently as October 2014. The bill for Davis' four-day trip to Baku, Azerbaijan, was $24,000.

"We'll see what the ultimate is in terms of what the committee says, but, you know, I don't know about other members, but for me it had no particular," Davis said, trailing off. "The people who asked me to go, they have a charter school in my district and we've interacted with them, I guess, a bit. Actually, I've been to the schools, spoke to the kids, looked around, and gone to other things."

"Beyond that ... I've been a great friend of the Armenian community," he continued. "They don't have a lot of love for Turkey, and so learning about establishing relationships and even, ultimately, perhaps there will be some trade opportunities, but beyond that it really means nothing else."